Our long-term objectives on this project are to explore the molecular bases of membrane structure and function, with emphasis on the application of such information problems of immunology, hematology, and lymphocyte biology. We propose to carry out the following specific studies: 1) to determine the rates of uptake of H3-methochlorpromazine by intact human erythrocytes to test the bilayer couple hypothesis, which predicts a differential distribution of the compound in the two half-layers of the bilayer membrane, and a slow flip-rate between them; 2) to investigate possible differences in membrane mobility of the Rho(D) antigen in intact erythrocytes from Rh positive newborn compared to adult humans; 3) to study differences in the mobilities of components in the membranes of rabbit and human reticulocytes as compared to their mature erythrocyte counterparts; and (4) to study the ultrastructural localization, by immunoelectron microscopy, of mechanochemical proteins in lymphocytes that have undergone membrane capping reactions. BIBLIOGRAPHIC REFERENCES: A disulfide-bridge bifunctional imidoester as a reversible cross-linking reagent, Arnold Ruoho, Paul A. Bartlett, Anne Dutton, and S.J. Singer, Biochem. Biophys. Res. Commun. 63:417 (1975). Detection and ultrastructural localization of human smooth muscle myosin-like molecules in human non-muscle cells by specific antibodies, Richard G. Painter, Michael Sheetz and S.J. Singer, Proc. Nat. Acad. Sci. 721359 (1975).